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Date: Mon, 16 May 2011 18:09:43 +0200
From: Andi Kleen <andi@firstfloor.org>
To: Andy Lutomirski <luto@MIT.EDU>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
        Andi Kleen <andi@firstfloor.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@amd64.org>
Subject: Re: [PATCH v4 0/6] Micro-optimize vclock_gettime
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>  - Don't turn off frame pointers in vDSO code.

Why? Note frame pointers are costly on some CPUs, like Atom.

Also unlike the primitive state of the kernel the user space debuggers
are usually advanced enough to support dwarf2 unwinding.

-Andi